3-dimensional displaying apparatus using line light source

ABSTRACT

The present disclosure relates to a 3-dimensional displaying apparatus using line light sources, which includes: a display panel having a plurality of pixels; a backlight panel having a plurality of line light sources disposed to be spaced apart from each other by a predetermined distance, the backlight panel being spaced apart from one surface of the display panel; and a distance-adjusting unit for adjusting a distance between the backlight unit and the display panel. According to the present disclosure, it is possible to display autostereoscopic images which may minimize the quality deterioration of the 3-dimensional images according to the change of distance from an observer to the 3-dimensional displaying apparatus, which is a problem of a displaying apparatus implementing 3-dimensional images by using a general parallax separating unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.13/440,023 filed on Apr. 5, 2012, which claims the benefit of KoreanPatent Application No. 10-2011-0073576, filed on Jul. 25, 2011, theentire disclosure of which is incorporated herein by reference for allpurposes.

BACKGROUND

1. Field

The present disclosure relates to a 3-dimensional (cubic) displayingapparatus, and more particularly, to a glasses-free (or,autostereoscopic) 3-dimensional displaying apparatus using line lightsources, which may minimize the deterioration of quality of a3-dimensional image caused by the change of distance from the3-dimensional displaying apparatus by an observer.

2. Description of the Related Art

As the demand for displaying apparatuses capable of 3-dimensional imagesto give an actual stereoscopic effect not realized by a 2-dimensionalimage is increasing, displaying apparatuses capable of expressing3-dimensional images are being developed.

While staring at an object present in the natural world with right andleft eyes, a human may have a stereoscopic feeling since both eyes havedifferent viewing angles. Image information of objects with slightlydifferent viewing angles forms an image on the retina through the rightand left eyes, and the information of the formed stereo vision istransferred through the optic nerve to the brain to give a stereoscopiceffect.

In detail, a 3-dimensional image is generally formed by means of thestereo vision principle through both eyes. Here, there has been proposeda displaying apparatus which may exhibit a cubic image by using thebinocular disparity occurring due to the face that both eyes are spacedapart by about 65 mm. To describe the implementation of 3-dimensionalimages in more detail, right and left eyes looking the displayingapparatus see different 2-dimensional images. If two images aretransferred through the retina to the brain, the brain fuses two imagesexactly to regenerate the original 3-dimensional image in depth andrealistically, and this phenomenon is generally called stereography.

In a conventional glass-free 3-dimensional displaying apparatus, aparallax separating unit is disposed at the front of an existing2-dimensional displaying apparatus to transmit different parallax imagesto the left eye and the right eye of an observer so that the observermay receive an actual 3-dimensional image. The parallax separating unitused for giving such a stereoscopic effect may be a parallax barrierplate or a lenticular lens sheet. The example where a parallax barrierplate is used as the parallax separating unit to implement a3-dimensional image is shown in FIG. 1.

FIG. 1 shows an implementing principle of a 3-dimensional imageinformation displaying device with two viewing zones as a conventionalexample. Referring to FIG. 1, the conventional 3-dimensional imageinformation displaying device 100 with two viewing zones includes ageneral 2-dimensional display panel 110 and a parallax barrier plate 130disposed to be spaced apart from the front surface of the display panel110. The pixels formed on the display panel 110 are composed of left eyeimage pixels 13 and right eye image pixels 15. The parallax barrierplate 130 has an open region and a barrier region, and the imageinformation emitting from the left eye image pixel 13 and the right eyeimage pixel 15 passes through the open region and does not pass throughthe barrier region. The image information passing through the openregion reaches a designed observation distance to be focused thereat.Among locations of an observer in the designed observation distance, thelocation A allows only the image information of the left eye to beobserved, and the location B allows only the image information of theright eye to be observed.

However, such a method of displaying a 3-dimensional image by means ofparallax separation using the parallax barrier plate 130 has severalproblems which should be solved. First, in a case where the eyes movehorizontally so that the left eye is located at the location D and theright eye is located at the location E, the image information emittingfrom the left eye image pixel 13 and the right eye image pixel 15 aresimultaneously applied to the left eye and the right eye as shown bydotted lines in the figure. As a result, it is impossible to see a clear3-dimensional image. This phenomenon is called that a crosstalk occursbetween viewing zones.

Second, in a case where the observer moves horizontally so that the lefteye of the observer is located at the location B and the right eye islocated at the location C, the left eye watches the image informationemitting from the right eye image pixel 15, and the right eye watchesthe image information emitting from the left eye image pixel 13. As aresult, a reversed stereovision is obtained, and it is impossible towatch normal 3-dimensional image information.

Third, the image in the corresponding viewing zone does not have regularbrightness, and when the eyes move horizontally, the brightness of theimage changes. This problem will be described in detail with referenceto FIG. 2.

FIG. 2 is a light distribution graph between viewing zones of a3-dimensional image obtained using a conventional parallax separatingunit. Here, the horizontal axis represents a horizontal location at anobservation distance, and the vertical axis represents the intensity oflight. Referring to FIG. 2, in a case where the left eye and the righteye respectively located at a first viewing zone (shown with a solidline) and a second viewing zone (shown with a dotted line) move right orleft in the horizontal direction, the brightness of the correspondingimage decreases, and a crosstalk problem also occurs since theinformation of the image is mixed with the information of a neighboringviewing zone.

In addition, if the observer becomes closer or farther by just 5% of theoptimum distance from the display, the viewing zone separation greatlydeteriorates, compared with the separation at the optimum distance (seeFIGS. 4A to 4D, where the crosstalk increases).

The above description is based on the example where the parallax barrierplate is used as the parallax separation unit, but the same problem asabove occurs even when a lenticular lens is used.

A method of displaying a 3-dimensional image using line light sources,without using a parallax separation unit, is also widely known in theart (U.S. Pat. No. 5,897,184). However, this method also has theproblems of the 3-dimensional image obtained by the parallax separationunit.

SUMMARY

The present disclosure is directed to providing a 3-dimensionaldisplaying apparatus using line light sources, which may minimize thedeterioration of quality of the 3-dimensional image even though anobserver changes a distance from the 3-dimensional displaying apparatusin the forward or rearward direction.

In order to solve the quality deterioration of a 3-dimensional imagewhich may occur when an observation distance of an observer from thedisplay changes, line light sources are disposed to be spaced apart fromeach other at the rear of the display panel, and a backlight composed ofline light sources which may operate at different time points isdisposed according to the location of the observer, so that the observermay watch the 3-dimensional image without quality deterioration eventhough the location of the observer changes from the display in thedepth direction. At this time, a pupil tracking system may be providedto track the location of the pupil of the observer in real timeaccording to the change of location of the observer, and the locationsof the line light sources in the depth direction are changed so that theline light sources may operate at different depths from the displaypanel, whereby the observer may continuously watch a suitable3-dimensional image even though the eyes of the observer moves.

In detail, in one aspect, there is provided a 3-dimensional displayingapparatus, which includes: a display panel having a plurality of pixels;a backlight panel having a plurality of line light sources disposed tobe spaced apart from each other by a predetermined distance, thebacklight panel being spaced apart from one surface of the displaypanel; and a distance-adjusting unit for adjusting a distance betweenthe backlight unit and the display panel.

The 3-dimensional displaying apparatus may further include a locationtracking unit for tracking a location of an observer and feeding backthe tracked location to the distance-adjusting unit, and thedistance-adjusting unit may adjust the distance based on the trackedlocation.

The location tracking unit may be a face tracking unit which tracks alocation of the face of the observer or a pupil tracking unit whichtracks a location of the pupil of the observer.

The line light sources may be formed as light-emitting sources formed byLED, OLED or FED, or line light sources each having an oriented surfacelight source generating device and an optical element formed at thefront surface of the oriented surface light source generating device.

In another aspect, there is provided a 3-dimensional displayingapparatus, which includes: a display panel having a plurality of pixels;and a backlight panel spaced apart from one surface of the displaypanel, wherein the backlight panel has a plurality of line light sourcesets disposed to be spaced apart from each other on different planesperpendicular to the display panel, and wherein each of the line lightsource sets includes a plurality of line light sources disposed to bespaced apart from each other on the same plane.

The backlight panel may be divided into a plurality of backlight panelsspaced apart from each other, each of the divided backlight panelshaving one line light source set.

The 3-dimensional displaying apparatus further may include a locationtracking unit for tracking a location of an observer and feeding backthe tracked location to the backlight panel, and the backlight panel mayselectively operate the line light source sets based on the trackedlocation.

The location tracking unit may be a face tracking unit which tracks alocation of the face of the observer or a pupil tracking unit whichtracks a location of the pupil of the observer.

The line light sources may be formed as light-emitting sources formed byLED, OLED or FED, or line light sources each having an oriented surfacelight source generating device and an optical element formed at thefront surface of the oriented surface light source generating device.

In still another aspect, there is provided a 3-dimensional displayingapparatus, which includes: a display panel having a plurality of pixels;and a backlight panel spaced apart from one surface of the displaypanel, wherein the backlight panel includes an oriented surface lightsource emitting an oriented light in a direction perpendicular to thedisplay panel; and an optical element formed between the orientedsurface light source and the display panel, wherein the light emittingfrom the surface light source passes through the optical element andforms a line light source set composed of a plurality of line lightsources disposed to be spaced apart from each other by a predetermineddistance, on a plane perpendicular to the display panel between theoptical element and the display panel, and wherein the distance betweenthe line light source set and the display panel is adjusted according toan electric signal applied to the optical element.

The optical element may include a concave lens type substrate having acylinder shape, a flat plate type substrate, and a liquid crystal layerformed between the concave lens type substrate and the flat plate typesubstrate, and the electric signal may be applied by an electrodedisposed between the concave lens type substrate and the flat plate typesubstrate.

The optical element may be a liquid crystal lens, the liquid crystallens may include a liquid crystal layer formed between the substrates,and the electric signal may be applied by an electrode having apredetermined pattern disposed between the substrates.

The 3-dimensional displaying apparatus may further include a lenticularlens between the liquid crystal lens and the display panel.

The 3-dimensional displaying apparatus may further include a locationtracking unit for tracking a location of an observer and feeding backthe tracked location to an electric signal applying unit, and theelectric signal applying unit may adjust the electric signal applied tothe optical element based on the tracked location.

The location tracking unit may be a face tracking unit which tracks alocation of the face of the observer or a pupil tracking unit whichtracks a location of the pupil of the observer.

The 3-dimensional displaying apparatus may further include afocus-adjusting liquid crystal cell formed between the display panel andthe backlight panel, and the distance between the line light sources andthe display panel may be adjusted according to the electric signalapplied to the focus-adjusting liquid crystal cell.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the disclosedexemplary embodiments will be more apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a cross-sectional view showing an implementing principle of aconventional 3-dimensional displaying apparatus using a parallax barrierplate;

FIG. 2 is a light distribution graph between viewing zones of a3-dimensional image obtained using the conventional parallax separatingunit;

FIG. 3 is a top view showing an autostereoscopic display using linelight sources according to an embodiment of the present disclosure;

FIGS. 4A to 4D are graphs showing the change of a viewing zone when anobserver moves forwards or rearwards based on the optimum distance froman display panel in the conventional art;

FIG. 5 is a conceptual view showing a two view 3-dimensional displayingapparatus using line light sources with different distances according toan embodiment of the present disclosure;

FIG. 6 is a conceptual view for illustrating an operation principle ofthe two view 3-dimensional displaying apparatus according to anembodiment of the present disclosure;

FIG. 7 is a conceptual view showing a four view 3-dimensional displayingapparatus using line light sources with different distances according toan embodiment of the present disclosure;

FIGS. 8A to 8C are first conceptual views for illustrating animplementation method of a distance-adjusting line light sourceaccording to an embodiment of the present disclosure;

FIGS. 9A and 9B are second conceptual views for illustrating animplementation method of a distance-adjusting line light sourceaccording to an embodiment of the present disclosure; and

FIG. 10 is a third conceptual view for illustrating an implementationmethod of a distance-adjusting line light source according to anembodiment of the present disclosure.

<Detailed Description of Main Elements> 10: pixel 13: left eye imagepixel 15: right eye image pixel 30, 50, 60, 70: line light source 110:general 2-dimensional display panel 130: parallax barrier plate 310:display panel 330, 510, 520, 530, 610, 620, 630, 710, 720, 730, 810,860: backlight panel 650: location tracking unit 900: line light sourcedevice of this disclosure 910: surface light source 920: polarizingplate 930: flat plate type substrate 940: liquid crystal layer 950:concave lens type substrate 960: liquid crystal lens 961: secondsubstrate 963: liquid crystal layer 965: first substrate 970: lenticularlens sheet 1000: focus-adjusting liquid crystal cell

DETAILED DESCRIPTION

Exemplary embodiments now will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsare shown. The present disclosure may, however, be embodied in manydifferent forms and should not be construed as limited to the exemplaryembodiments set forth therein. Rather, these exemplary embodiments areprovided so that the present disclosure will be thorough and complete,and will fully convey the scope of the present disclosure to thoseskilled in the art. In the description, details of well-known featuresand techniques may be omitted to avoid unnecessarily obscuring thepresented embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. Furthermore, the use of the terms a, an, etc. doesnot denote a limitation of quantity, but rather denotes the presence ofat least one of the referenced item. The use of the terms “first”,“second”, and the like does not imply any particular order, but they areincluded to identify individual elements. Moreover, the use of the termsfirst, second, etc. does not denote any order or importance, but ratherthe terms first, second, etc. are used to distinguish one element fromanother. It will be further understood that the terms “comprises” and/or“comprising”, or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art. It will be further understood that terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and the present disclosure, and will notbe interpreted in an idealized or overly formal sense unless expresslyso defined herein.

In the drawings, like reference numerals denote like elements. Theshape, size and regions, and the like, of the drawing may be exaggeratedfor clarity.

FIG. 3 is a top view showing an autostereoscopic display using linelight sources according to an embodiment of the present disclosure.Referring to FIG. 3, the 3-dimensional displaying apparatus according tothe present disclosure includes a display panel 310 displayinginformation of two or more viewing zones, and a backlight panel 330having a plurality of line light sources 30 disposed to be spaced apartby a predetermined distance from the rear surface of the display panel310. The plurality of line light sources 30 of the backlight panel 330are disposed at regular intervals so that the viewing zones of the imageinformation formed on the display panel 310 are separated at a designedobservation distance. FIG. 3 shows the concept where, regarding the twoviewing zone image information, the left viewing zone (the first viewingzone) and the right viewing zone (the second viewing zone) are separatedat the designed observation location.

The size E of each viewing zone is basically 65 mm which is an averagedistance between eyes of a human, but the size may be set to be smallerthan the average distance between eyes when viewing zones are classifiedmore than two. In order to normally observe the images of two viewingzones at the observation location, the relational expression among adesigned observation distance Lo from the display panel 310, a size E ofeach viewing zone, a distance d between the backlight panel 330 havingthe line light sources 30 and the display panel 310, a pixel size Wp ofthe display panel 310, and a distance Ls between neighboring line lightsources 30 satisfies the following equation.

$\begin{matrix}{L_{s} = {2W_{p}\frac{L_{o} + d}{L_{o}}}} & {{Equation}\mspace{14mu} 1} \\{d = \frac{W_{p}L_{o}}{E - W_{p}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

Equations 1 and 2 do not consider upper and lower substrates of thedisplay panel 310 or materials coated to the front of the line lightsources 30 of the backlight panel 330, and therefore a correctedrelational expression should be used when designing an actual viewingzone.

In the viewing zone designed using the relational expression, thedistance d between the line light sources 30 and the display panel 310is determined according to an optimum observation distance Lo of theobserver, as shown in Equation 2. If the horizontal location of theobserver changes from the optimum distance, a reverse cubic image mayoccur and the brightness of the viewing zone may become irregular, sovarious attempts have been made to solve these problems in associationwith a pupil tracking system. However, the quality deterioration of a3-dimensional image caused by the change of the optimum observationdistance and solutions for this problem has not yet fully discussed.

In the case where a viewing zone is formed when a line light source isused and the line light source moves from the optimum distance in theforward or rearward direction, at an Optimum Viewing Distance OVD formedwhen a glass-free 3-dimensional viewing zone is initially designed, theviewing zone is formed to be close to a rectangular shape so that theimage of each viewing point may be observed with a minimized crosstalk.However, when all 3-dimensional pixels are considered, if any pixeldeparts from the Optimum Viewing Distance OVD, it is difficult to form acommon viewing zone for the 3-dimensional pixels. At this time, therectangular viewing zone changes into a triangular shape as shown inFIGS. 4A to 4D, and so it is difficult to realize the minimization ofcrosstalk, which is initially aimed. FIGS. 4A to 4D are graphs showingpixels of the viewing zone according to the simulation condition andresultant distance. The graph of FIGS. 4A to 4D show the change of theviewing zone when an observer moves forwards or rearwards based on theoptimum distance from the display panel in the conventional art. Thesimulation conditions of FIGS. 4A to 4D are as follows.

Simulation Condition

-   -   pixel pitch Wp: 0.45 mm    -   optimum observation distance Lo: 1000 mm    -   interval of viewing points E: 65 mm    -   number of viewing zones: 2    -   interval between the line light source and the display panel d:        6.9713 mm    -   interval between line light sources Ls: 0.906 mm    -   line width W_(LS) of the line light sources: 0.15 mm

FIG. 4A is a graph showing the shape of the viewing zone according to ahorizontal location at an optimum observation distance 1000 mm. FIGS. 4Bto 4D respectively show the shape of the viewing zone at the optimumlocation which is changing as the distance increases by 1%. For example,the uniform region in one viewing zone decreases as the optimum viewingzone changes less than 3%, and so the crosstalk which is an overlappingphenomenon between neighboring viewing zones increases. Though not shownin the graph, even when the observation distance changes less than 3%from the optimum distance, the result will be similar to those of FIGS.4B to 4D.

When a 3-dimensional image is obtained at 1000 mm (1 M) observationdistance, if the quality of the 3-dimensional image deteriorates justwith forward and rearward movement of several ten millimeters, theobserver has too small freedom and should watch a long-time3-dimensional image without forward or rearward movement.

If d is eliminated from Equations 1 and 2, Equation 3 below is obtained.

$\begin{matrix}{L_{s} = {2\; W_{p}\frac{E}{E - W_{p}}}} & {{Equation}\mspace{14mu} 3}\end{matrix}$

As shown in Equation 3, the optimum observation distance Lo and d(distance between the line light sources and the display panel) satisfythe proportionate relationship and offset each other, and Ls (distancebetween the line light sources) is associated with only the pixel widthWp and the interval E of viewing points so that the optimum observationdistance may be adjusted by changing only the distance d between theline light sources and the display panel while maintaining the distanceLs between the line light sources consistently.

Equations 1 to 3 are relational expressions about variables for twoviewing zones, and they may be changed to relational expressions about Nviewing zones as shown in Equations 4 to 6 below.

$\begin{matrix}{L_{s} = {{NW}_{p}\frac{d + L_{o}}{L_{o}}}} & {{Equation}\mspace{14mu} 4} \\{d = \frac{W_{p}L_{o}}{E - W_{p}}} & {{Equation}\mspace{14mu} 5} \\{L_{s} = {N\; W_{p}\frac{E}{E - W_{p}}}} & {{Equation}\mspace{14mu} 6}\end{matrix}$

Equations 1 to 3 may be recognized as expressions obtained bysubstituting N viewing zones of Equations 4 to 6 with two viewing zones.This example will be described as follows with reference to FIG. 5.

FIG. 5 is a conceptual view showing a two view 3-dimensional displayingapparatus using line light sources with different distances according toan embodiment of the present disclosure. FIG. 5 shows that backlightpanels 510, 520 and 530 having line light source sets at differentdistances are associated with different optimum distances Lo1 to Lo3from the display panel 310. The line light source sets at differentdistances are arranged on each plane so that a distance betweenneighboring line light sources is identical. The principle of allowingan observer to watch an optimum 3-dmensional image by using the linelight source sets at different distances will be described below withreference to the conceptual view of FIG. 6.

FIG. 6 is a conceptual view for illustrating an operation principle ofthe two view 3-dimensional displaying apparatus according to anembodiment of the present disclosure. Referring to FIG. 6, a3-dimensional display panel (a dotted portion) includes backlight panels610, 620 and 630 having line light source sets at different distancesand a display panel 310 disposed to be spaced apart from the backlightpanels 610, 620 and 630 by a predetermined distance. In addition, alocation tracking unit 650 tracks the location of the observer and feedsback the location to the 3-dimensional display panel. The locationtracking unit may be a pupil tracking unit for tracking the location ofthe pupil of the observer or a face tracking unit for tracking the faceof the observer. In this embodiment, the location tracking unit tracksthe location of the pupil. Among the backlight panels 610, 620 and 630,a backlight panel including the line light source set forming a viewingzone in the fed-back pupil observation distance of the pupil isselectively operated. In other case, the backlight panel is effectivelymoved to form a viewing zone in the pupil observation distance.

In the 3-dimensional displaying apparatus as described above, in thecase where the observer is at the location P2 spaced apart from thedisplay panel, only the line light source set of the backlight panel 620disposed to be spaced apart from the display panel 310 by d1 turns on oreffectively moves to the location d1. If there are several line lightsource sets, line light source sets at the other locations are adjustedto turn off. As a result, if the left and right eyes of the observer arelocated respectively at the first viewing zone and the second viewingzone in P2 to observe the display panel, the observer may watch anoptimum 3-dimensional image.

Meanwhile, if the observer moves closer to the location P3 from thedisplay panel 310, the line light source set of the backlight panel 630at the location d2 from the display panel 310 turns on, and line lightsource sets at the location d1 turn off. In other case, when there isonly a single line light source, the backlight panel at the location d1is effectively moved to the location d2 in a physical way or by using aliquid crystal lens. From the above, even at the location P3, theobserver may watch a 3-dimensional image having the same quality as inthe case of watching at the location P2.

In the case where the observer observes at the location P1 spaced apartfrom the display panel 310 in the same way, the line light source setsof the backlight panels 620 and 630 at the locations d1 and d2 turn off,and only the line light source set of the backlight panel 610 at thelocation d3 turns on so that a clear 3-dimensional image may be watchedfrom the display panel 310 even at the location P1. In addition, theabove method may be implemented by effective distance change of a singleline light source set.

In the case of FIGS. 5 and 6, line light source sets are provided atthree locations with different distances so that an observer operatesonly a line light source set close to the optimum observation distanceof each line light source set to optimize the viewing zonecharacteristics and minimize the crosstalk. As another method, a singleline light source set is used, and an observer may effectively change adistance of the line light source by physically moving the line lightsource set or by optically using a liquid crystal lens or the like sothat the line light source set may form an optimum viewing zoneaccording to the observation distance of the observer.

The above description is based on the two view 3-dimensional image, butit may also be applied to more than two viewing zones. This may be shownusing the relational expressions of Equations 4 to 6. For example, FIG.7 is a conceptual view showing a four view 3-dimensional displayingapparatus using line light sources with different distances according toan embodiment of the present disclosure. Its operation principle isidentical to that of FIG. 6.

The line light source sets disposed with different distances asillustrated in FIGS. 5 to 7 may be implemented in various ways. Amongthem, available embodiments will be described with reference to FIGS.8A-8C, 9A-9B, and 10.

FIGS. 8A to 8C show an example where line light sources in a distancedirection are actually implemented as a light-emitting line light sourceset. FIG. 8A is a sectional view showing line light sources formed at abacklight panel 810 spaced apart from the display panel 310 by apredetermined distance. Even though the line light sources used hereinare formed on one plane, an interval-adjusting element 820 for thedisplay panel 310 may be provided to feed back the location of anobserver through a positioning system of the observer, and an intervalbetween the display panel 310 and the backlight panel 810 having linelight sources is adjusted so that an optimum 3-dimensional image may beobserved at the corresponding location. In this way, the location of theobserver in the distance direction, conceptually illustrated in FIGS. 5to 7, may be adjusted. The interval-adjusting element 820 for adjustingthe interval between the display panel 310 and the line light sources ofthe backlight panel 810 may be an actuator or PZT which is apiezoelectric element.

FIG. 8B shows another method for implementing a light-emitting lightsource set. FIG. 8B shows several transparent backlight panels 830, 840and 850 respectively having a line light source set and piled up, andthe display panel 310 spaced apart from the line light source set by apredetermined distance. The distance from the display panel 310 to theobserver is checked, and this signal is fed back to operate only a partof the transparent backlight panels 830, 840 and 850 so that theobserver may watch an optimum 3-dimensional image even though moving inthe distance direction. The transparent backlight panel may be an OLEDwhich uses transparent electrodes.

FIG. 8C shows another method for implementing a light-emitting linelight source set. In a medium 860 with a consistent thickness,light-emitting sources 50, 60 and 70 are disposed on a plane to bespaced apart from each other by a predetermined distance in the distancedirection, and line light sources at locations with different distancesare selectively operated according to the location information of theobserver so that the observer may watch an optimum 3-dimensional imageaccording to the observer location in the distance direction, which isconceptually illustrated in FIGS. 5 to 7. The line light sources ofFIGS. 8A-8C may be LED, OLED, FED, or the like which may be implementedin a light emitting type.

Meanwhile, line light sources with different distances from the displaypanel may also be manufactured using a surface light source with goodorientation and an electric optical plate which adjusts a focusingdistance according to an electric signal, even though the line lightsources are not light-emitting type. FIGS. 9A and 9B show this example.

FIGS. 9A and 9B are second conceptual views for illustrating animplementation method of a distance-adjusting line light sourceaccording to an embodiment of the present disclosure. FIG. 9A shows thecase where an optical plate including a surface light source 910 withgood orientation, a polarizing plate 920 disposed at the front of thesurface light source 910, a concave lens type substrate 950 disposed atthe front of the polarizing plate 920 and having a cylinder shape, and aliquid crystal layer 940 formed between the concave lens type substrate950 and a flat plate type substrate 930, is used. In this case, theextraordinary refractive index of the liquid crystal layer 940 isgenerally greater than the refractive index of the flat plate typesubstrate 930 and therefore plays a role of a cylindrical convex lensbased on the liquid crystal layer 940. Though not shown in the figure,transparent electrodes or metal wires are disposed at the inner sides ofboth substrates 950 and 930 which are electric optical plates.Therefore, the focusing distance of the light emitting from thebacklight may be adjusted by changing the arrangement status of theliquid crystal layer and thereby changing the refractive index inresponse to an electric field formed by applying a voltage according toan external electric signal determined by the location of the observer.As a result, line light source sets at different locations in thedistance direction, which are conceptually illustrated in FIGS. 5 to 7,may be implemented.

FIG. 9B shows the case where a lenticular lens sheet 970 and a liquidcrystal lens 960 having a pitch designed according to the intervalbetween the formed line light sources are piled up and disposed at thefront surface of a surface light source 910 with good orientation tomake line light sources. FIG. 9B is different from FIG. 9A in the pointthat the focusing distance may be changed more due to the effects of twokinds of lens spaced apart from each other, and so the locations of theline light sources in the distance direction may be changed further incomparison to the embodiment of FIG. 9A. In this case, the liquidcrystal lens 960 includes a first substrate 965, a second substrate 961,and a liquid crystal layer 963 formed between the first and secondsubstrates 965 and 961. Electrode structures are formed between bothsubstrates 961 and 965 and the liquid crystal layer 963 so that thelocation of line light sources in the distance direction which areformed after the lenticular lens sheet 970 may be changed by adjustingthe arrangement status of the liquid crystal layer 963 according to theapplied voltage. The liquid crystal lens 960 changes the lens effectwhen an electric field is applied according to the upper and lowerelectrode structures, and may be a gradient index (GRIN) type liquidcrystal lens which changes locations of line light sources in thedistance direction. In addition, the liquid crystal lens 960 may beconfigured by a liquid crystal layer 940 formed between the concave lenstype substrate 950 and the flat plate type substrate 930 which have afixed cylinder shape as shown in FIG. 9A. In this case, theextraordinary refractive index of the liquid crystal layer 930 isgenerally greater than the refractive index of the flat plate typesubstrate 930 and therefore plays a role of a cylindrical convex lensbased on the liquid crystal layer. At this time, the location in thedistance direction where line light sources are formed may be changed byadjusting the arrangement of the liquid crystal layer according to theapplied electric field. FIG. 9B shows the case where a lenticular lenssheet 970 is disposed between the display panel 310 and the liquidcrystal lens 960, but the liquid crystal lens 960 and the lenticularlens sheet 970 may also be used in a reversed order.

The surface light source 910 with good orientation shown in FIGS. 9A and9B may be configured to generate light similar to collimated light inorder to maximize the efficiency of the electric optical plate adjustingthe focusing distance according to the electric signal (or, in order toconcentrate light to the line light source) or may be configured with aline light source set identical to the period of the cylinder convexlens.

In particular, the embodiments of the line light sources shown in FIGS.8B, 8C and 9A may have a 2D/3D conversion mode. For example, in order tooperate in a 3D mode, in FIGS. 8B and 8C, only line light source sets indifferent distances are operated, and in FIG. 9A, the locations in thedistance direction of line light sources formed after passing throughthe concave lens type substrate according to a suitable electric signalare changed according to the location of the observer. Meanwhile, inorder to operate in a 2D mode, in FIGS. 8B and 8C, line light sources indifferent distances are operated, and in FIG. 9A, an electric signal isapplied so that the concave lens type substrate 950 and the liquidcrystal layer 940 having a cylinder shape have the same refractiveindex, or both media are selected to have the same refractive indexwithout an electric signal. At this time, the lens effect is eliminated,and therefore the mode is converted to a mode in which a general 2Dimage is watched instead of 3D image. In addition, in all embodiments ofFIGS. 8A-8C and 9A-9B, a variable diffusion plate (e.g., PDLC or thelike) may be used between the display panel and the line light sourcesor a variable liquid crystal lens for the conversion between the 2D modeand the 3D mode.

FIG. 10 is a third conceptual view for illustrating an implementationmethod of a distance-adjusting line light source according to anembodiment of the present disclosure. In FIG. 10, the system where thedistance between an observer and an operating line light source set or adisplay panel of line light sources is effectively changed according tothe location of the observer as illustrated in FIGS. 8A-8C and 9A-9B iscalled a line light source device 900 (810 in FIG. 8A, and 910 to 950 inFIG. 9A), and a focus-adjusting liquid crystal cell 1000 configured witha liquid crystal layer 1020 formed between both substrates 1010 and 1030according to the application of an electric field may be added betweenthe display panel 310 and the line light source device 900. In thiscase, the actual distance between the line light sources and the liquidcrystal display panel implemented in FIGS. 8A-8C and 9A-9B may bechanged according to the electric field applied to the focus-adjustingliquid crystal cell 1000, and therefore, as described above, thelocation information of the observer may be fed back to adjust thevoltage applied to the focus-adjusting liquid crystal cell 1000 andthereby adjust the distance between the liquid crystal display panel 310and the line light source device 900 so that the observer may watch anoptimum 3-dimensional image even though changing a location in thedistance direction.

According to the present disclosure, it is possible to displayglass-free 3-dimensional images which may minimize the qualitydeterioration of the 3-dimensional images according to the change ofdistance from an observer to the 3-dimensional displaying apparatus,which is a problem of a displaying apparatus implementing 3-dimensionalimages by using a general parallax separating unit. While the exemplaryembodiments have been shown and described, it will be understood bythose skilled in the art that various changes in form and details may bemade thereto without departing from the spirit and scope of the presentdisclosure as defined by the appended claims.

In addition, many modifications can be made to adapt a particularsituation or material to the teachings of the present disclosure withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the present disclosure not be limited to the particular exemplaryembodiments disclosed as the best mode contemplated for carrying out thepresent disclosure, but that the present disclosure will include allembodiments falling within the scope of the appended claims.

What is claimed is:
 1. A 3-dimensional (3D) display apparatus,comprising: an image display panel having a plurality of pixels; and abacklight panel spaced apart from a surface of the image display panel,wherein the backlight panel comprises a first light emitting set and asecond light emitting set, the second light emitting set comprising aplurality of light emitting units arranged to create a first visualfield and a second visual field, and wherein two adjacent light emittingunits are placed apart such that light from one of the two adjacentlight emitting units creating the first visual field passes through afirst pixel set of the image display panel, and light from the other ofthe two adjacent light emitting units creating the second visual fieldcloser to the image display panel than the first visual field passesthrough the first pixel set, wherein the backlight panel is configuredto activate the first light emitting unit set, in response to detectinga motion approaching the image display panel, and to activate the secondlight emitting unit set, in response to detecting a motion moving awayfrom image display panel, the first light emitting unit being closer tothe backlight panel than the second light emitting unit.
 2. The3-dimensional display apparatus according to claim 1, wherein a distancebetween two adjacent light emitting units is larger than a pitch of thepixel.
 3. The 3-dimensional display apparatus according to claim 1,wherein the plurality of light emitting units are arranged to operate atthe same time.
 4. The 3-dimensional display apparatus according to claim1, wherein the plurality of light emitting units are spaced apart fromeach other at regular intervals.
 5. The 3-dimensional display apparatusaccording to claim 1, wherein the plurality of light emitting units areplaced on a plane parallel to the image display panel.
 6. The3-dimensional display apparatus according to claim 1, wherein the lightemitting units comprise line light sources or a surface light source. 7.The 3-dimensional display apparatus according to claim 1, furthercomprising: a tracking unit configured to track a location of anobserver to feed the tracked location back to the backlight panel. 8.The 3-dimensional display apparatus according to claim 7, wherein thetracking unit comprises a face tracking unit or an eye tracking unit. 9.The 3-dimensional display apparatus according to claim 7, furthercomprising: a moving unit configured to move the plurality of the lightemitting units based on the tracked location of the observer.
 10. A3-dimensional (3D) display apparatus, comprising: an image display panelhaving a plurality of pixels; and a backlight panel spaced apart from asurface of the image display panel, wherein the backlight panelcomprises: a first light emitting unit set comprising a plurality oflight emitting units creating a first visual field and a second visualfield; and a second light emitting unit set comprising a plurality oflight emitting units arranged to create a third visual field and afourth visual field, each of the plurality of light emitting units ofthe second light emitting unit set being spaced apart from one of thelight emitting units of the first light emitting unit set at aninterval, and wherein two adjacent light emitting units are placed apartsuch that light from one of the two adjacent light emitting unitscreating the first and third visual fields passes through a first pixelset of the image display panel, and light from the other of the twoadjacent light emitting units creating the second and fourth visualfields closer to the image display panel than the first and third visualfields passes through the first pixel set, wherein the backlight panelis configured to activate the first light emitting unit set, in responseto detecting a motion approaching the image display panel, and toactivate the second light emitting unit set, in response to detecting amotion moving away from image display panel, the first light emittingunit being closer to the backlight panel than the second light emittingunit.
 11. The 3-dimensional display apparatus according to claim 10,wherein a distance between two adjacent light emitting units of thefirst light emitting unit set is larger than a pitch of the pixel. 12.The 3-dimensional display apparatus according to claim 10, wherein theplurality of light emitting units of the first light emitting unit setare arranged to operate at the same time and the plurality of lightemitting units of the second light emitting unit set are arranged tooperate at the same time.
 13. The 3-dimensional display apparatusaccording to claim 10, wherein the first light emitting unit set and thesecond light emitting unit set are arranged to operate at differenttimes.
 14. The 3-dimensional display apparatus according to claim 10,wherein the plurality of light emitting units of the first lightemitting unit set are spaced apart from each other at regular intervals.15. The 3-dimensional display apparatus according to claim 10, wherein adistance between two adjacent light emitting units of the first lightemitting unit set is identical to a distance between two adjacent lightemitting units of the second light emitting unit set.
 16. The3-dimensional display apparatus according to claim 10, wherein theplurality of light emitting units of the first light emitting unit setare placed on a plane parallel to the image display panel.
 17. The3-dimensional display apparatus according to claim 10, wherein each ofthe light emitting units of the first light emitting unit setcorresponds in position to each of the light emitting units of thesecond light emitting unit set.